1. Field of the Invention
The present invention relates to a thermo-sensitive transfer ribbon for forming a dry type lettering sheet and particularly to a thermo-sensitive transfer ribbon through which letters or images with metallic luster can be formed on a lettering sheet film with poor wettability and high releasability, by utilizing a printing device with a thermal head installed therein such as a printer, a typewriter and a wordprocessor, each adopting a thermo-sensitive transfer method.
2. Description of Related Art
Conventionally, in order to obtain a dry type lettering sheet through which letters or images (abbreviated as transfer image hereinafter) thereon can be transferred on a target material, various thermo-sensitive transfer ribbons are proposed. The owner of the present invention has also proposed some of such thermo-sensitive transfer ribbons. For example, in U.S. Pat. No. 5,024,887, a thermo-sensitive transfer ink ribbon to be used for producing a dry type transfer material, is disclosed.
By applying the thermo-sensitive transfer ink ribbon disclosed in U.S. Pat. No. 5,024,887 to the ordinary thermal printing device, the transfer image which is composed of both a ink layer including carbon black and a transfer property control layer, is transferred onto a lettering sheet film having poor wettability and high releasability. Thereby, the dry type lettering sheet on which the transfer image is firmly formed, can be obtained. Here, the transfer image has black color because of the carbon black in the ink layer. Thereafter, the transfer image side of the lettering sheet above obtained is contacted to the target material and pressure is applied to the back side of the lettering sheet. As a result, the transfer image with black color on the lettering sheet is transferred to the target material.
And, in U.S. patent application Ser. No. 07/929,411 submitted by the owner of the present invention, a heat transferable inked ribbon for providing a pressure transferable laminate, the heat transferable inked ribbon being substantially as same as the above thermo-sensitive transfer ink ribbon, is also disclosed. Thus, by using this heat transferable inked ribbon, the lettering sheet on which the transfer image with black color is formed, can be obtained and thereby, the transfer image with black color is transferred to the target material.
In addition to the above, a thermo-sensitive transfer ink ribbon through which the letters or images with the metallic luster can be transferred to a paper sheet, is disclosed in Japanese Patent applications, laid-open Nos. Sho 63-30,288, Sho 63-49,481, Sho 63-62,785, Sho 63-69,691, Sho 63-230,389, Sho 63-237,994, Sho 63-297,090 and Hei 1-141,086.
However, both the thermo-sensitive transfer ink ribbon disclosed in U.S. Pat. No. 5,024,887 and the heat transferable inked ribbon disclosed in U.S. patent application Ser. No. 07/929,411, are utilized for forming the lettering sheet on which the transfer image colored black is transferred. Therefore, the transfer image transferred to the target material also becomes black. Here, though the black color image is generally used in the field of the lettering sheet, it is considered that the black color cannot strongly emphasize the image and especially make the image recognizable with high visibility.
Further, the thermo-sensitive transfer ink ribbon disclosed in each of Japanese Patent applications mentioned above, is used for printing the letters or images with the metallic luster only to the paper sheet, therefore, through such thermo-sensitive ink ribbon, the lettering sheet on which the transfer image with the metallic luster cannot be obtained.
As mentioned above, up to the present time, it is not proposed any thermo-sensitive transfer ribbons through which the lettering sheet having the transfer image with the metallic luster, the transfer image being emphasized and made recognizable with high visibility on the target material based on the metallic luster, can be obtained.